This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).<br/><br/>This Small Business Innovation Research (SBIR) Phase I project will combine the capabilities of Picarro's WS-CRDS (wavelength-scanned cavity ring down spectroscopy) instrumentation with Gas Chromatography (GC) - Combustion (C) technology. This new high-precision, but low cost analyzer will simultaneously measure hydrogen (D/H) and carbon (13C/12C) isotope ratios of organic molecules and provides critical insight into underlying biochemical processes. One important application is the administration of deuterium- and/or 13C-labeled organic compounds to a subject and the use of isotopic ratio monitoring to track the fate of the labeled compound across time and body tissues. Such high-precision measurements are currently obtained with Isotope Ratio Mass Spectrometers (IRMS), which are too large, expensive, and laborintensive for wide use. In addition, two separate IRMS systems are needed for simultaneous hydrogen and carbon isotopic measurements. Picarro's GC-C-CRDS analyzer will be a high-precision, small, and inexpensive single-system replacement for IRMS to quantify both hydrogen and carbon isotopes. <br/><br/>The broader impact of this research is the cost reduction in health care through the advancement of preventative medicine by enabling the large-scale use of stable isotopes as tracers for metabolic research studies and medical diagnosis (insulin resistance, for instance) through the availability of an inexpensive and high-performance isotopic analyzer for clinical deployment and the subsequent possibility of fast, local, advanced medical testing and diagnosis in remote and economically disadvantaged communities. After establishing the GC-C-CRDS analyzer in research laboratories with this grant, Picarro intends to extend its presence to hospitals, clinics, and biopharmaceutical laboratories.